Diagnostic and therapeutic work carried out under the first two years of this grant has led to the isolation of a specific group of insomniacs (tentatively labeled idiopathic). These insomniacs seem to be characterized mainly by atypical EEG and EMG recordings (e.g., excessive alpha intrusion into sleep, lack of sleep spindles, excessive or atypical frontalis EMG, etc.). Biofeedback training of the sensorimotor rhythm (SMR) carried out in the first two years of this grant seems to improve the sleep in some of these patients quite dramatically. The study proposed now plans to start with interviewing and testing 150 new insomniacs, carefully collecting data our previous work has suggested as relevant. About 100 of these insomniacs and ten good sleepers will then spend three nights in the laboratory. Besides standard sleep parameters, we plan to quantify alpha intrusion into sleep, SMR activity during waking and sleeping, and frontalis EMG activity during waking and sleeping. Interview data, psychological testing, and polygraphic results will be both factor-analyzed and cluster-analyzed, in an effort to develop empirically defined dimensions of insomnia. Specific treatment recommendations will be developed for each insomniac. Their success will be evaluated nine months later by telephone interview, sleep logs at home, and sleep records where indicated. Fifteen idiopathic insomniacs each will receive either SMR biofeedback or feedback of 18-25 cps EEG activity. Each of these 30 patients will sleep in the laboratory for three nights, twice more: immediately following biofeedback and nine months later. Each of the 30 patients will also be offered training in the other frequency after followup (partial crossover design). It is hoped that this study will significantly further our understanding of the diagnosis and treatment of primary insomnia. In addition, it will delineate parameters of successful SMR biofeedback by specifying what type of patient derives benefit from SMR feedback and which parameters of the feedback situation are related to success.